1. Field of the Invention
The present invention relates to a system, a method, and a program for editing a production schedule. Each of these receives an editing operation to be performed on production schedule data showing multiple items chronologically arranged therein.
2. Description of Related Art
In general, a planning section draws up a production schedule for manufacturing products from raw materials in a plant. For example, in an iron foundry there are various production processes, such as, a receiving process of raw materials including iron ore, an iron making process, a steel making process, a casting process, a rolling process, and a shipping process. The planning section draws up a production schedule indicating the order of processing products (including semi-finished products) in each of the production processes.
In a production schedule, items indicating products (including semi-finished products) are chronologically arranged. Examples of production schedules include the order of casts in a steel making process, the order of charges in a cast, the order of cycles in a hot-rolling process, the order of slabs in a cycle, and the order of slabs in a charge.
There is a prior art for assisting a planning section to draw up a production schedule. Hereinafter, examples of such prior art will be described.
Japanese Patent Application Publication No. Hei. 9-249903 proposes a scheduling method of demand and supply management for molten iron. In this scheduling method, based on demand conditions for molten iron in a steel making process on the demand side, operation conditions are set up for an iron making process that is an upstream process of the steel making process. In this way, an operating schedule in which an upstream process and a downstream process are swapped with each other is drawn up. This operation scheduling method makes it possible to draw up a schedule for demand and supply management for molten metal with high precision.
Japanese Patent Application Publication No. 2002-149223 proposes a production management support system. In this production management support system a processing route for a product is determined upon receipt of a product order from order input means. Then, based on the lead time and efficiency of the determined processing route, the delivery date for each process and the capability balance between processes are adjusted. This production management support system makes it possible to prepare an accurate production schedule in a short time.
Meanwhile, it would be convenient if a planning section can accept correction (edit) in a production schedule once prepared appropriately in accordance with a change in operation, and the like.
In general, even when a planner prepares a production schedule in accordance with an order of an orderer, the product produced on the basis of the production schedule may sometimes not satisfy the quantity or quality demanded by the orderer due to an occurrence of change in operation or the like.
In such case, the planner needs to correct (edit) the production schedule once prepared in order to satisfy the quantity or quality demanded by the orderer.
Because an order may consist of a huge number of items, a production schedule is sometimes edited by multiple planners. In this case, some of the multiple planners may insert, delete, or move the same item in the production schedule. As a result, so-called editing conflicts in which multiple editors simultaneously edit the same item occur.
In order to deal with such problems it has been considered to set a so-called preliminary assignment by which each of multiple editors is assigned, in advance, a limited section of a production schedule so as to be authorized to edit only his/her section.
However, such an approach is manually conducted in general and thus has a disadvantage because an opportunity for optimal scheduling may be missed. For this reason, such an additional condition as the preliminary assignment should be better omitted as much as possible.